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<span id="IPA-passes"></span><div class="header">
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Next: <a href="Tree-SSA-passes.html" accesskey="n" rel="next">Tree SSA passes</a>, Previous: <a href="Pass-manager.html" accesskey="p" rel="prev">Pass manager</a>, Up: <a href="Passes.html" accesskey="u" rel="up">Passes</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html" title="Index" rel="index">Index</a>]</p>
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<span id="Inter_002dprocedural-optimization-passes"></span><h3 class="section">9.4 Inter-procedural optimization passes</h3>
<span id="index-IPA-passes"></span>
<span id="index-inter_002dprocedural-optimization-passes"></span>

<p>The inter-procedural optimization (IPA) passes use call graph
information to perform transformations across function boundaries.
IPA is a critical part of link-time optimization (LTO) and
whole-program (WHOPR) optimization, and these passes are structured
with the needs of LTO and WHOPR in mind by dividing their operations
into stages.  For detailed discussion of the LTO/WHOPR IPA pass stages
and interfaces, see <a href="IPA.html">IPA</a>.
</p>
<p>The following briefly describes the inter-procedural optimization (IPA)
passes, which are split into small IPA passes, regular IPA passes,
and late IPA passes, according to the LTO/WHOPR processing model.
</p>
<table class="menu" border="0" cellspacing="0">
<tr><td align="left" valign="top">&bull; <a href="Small-IPA-passes.html" accesskey="1">Small IPA passes</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
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<tr><td align="left" valign="top">&bull; <a href="Regular-IPA-passes.html" accesskey="2">Regular IPA passes</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="Late-IPA-passes.html" accesskey="3">Late IPA passes</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
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